Basic JavaScript Learning

First, JS Basic classification

1. Constants

1.1 Integer constants: Binary Conversions (number.tostring (16)--parentheses are converted into several binary);

1.2 Real-type constants

1.3 Boolean value: True and false, lowercase;

1.4-Character constants: single and double quotes;

1.5 null: null--The value of the non-existent quantity returns null;

1.6 Special characters: non-realistic special characters with/start for control characters;

Second, the variable: mainly used as access data, to provide information storage container, divided into global variables and local variables.

2.1 Attention Points

2.11 variable name valid, must start with a caption, the middle can have numbers and underscores (_), no space +-comma or other symbols;

2.12 cannot use the keyword in JS as the variable name;

2.13 variables must be declared before using Var;

Third, operator

3.1 Arithmetic operators: Add, subtract, multiply, divide, take surplus (%), take counter-, take complement ~,++ sliding scale,--decrement;

3.2 comparison operator (result true or false):>, <, >=, <=, = =,! =;

3.3 Logical operators:! Take anti-,&& with, | | Or

3.4 String arithmetic;

Iv. Expressions: A collection of operators

V. BASIC statements

5.1 If-else Conditional statement

The format is: if (expression) {

Execute statement 1;

}else{

EXECUTE statement 2;

}

5.2 For Loop statement

Format: for (start condition; termination condition; variable change) {

Execute the statement;

}

5.3 Break statement: Jump out of a for or while

5.4 Continue statement: End the current loop and go to the next loop

5.5 Switch statement:

Format: switch (expression) {

Case value 1;

Statement 1;

Break

Case value 2;

Statement 2;

Break

。。。

Default

Statement N;

}

Vi. functions

JavaScript Basic Learning